Cap for ingot molds



Feb. 17, 1942-. RD ZWEIER' 2,273,551

CAP FOR INGOT MOLDS Filed June 14, 1959 2 Sheets-Sheet 1 Patented Feb. .17, 1942 CAP FOR, INGOT MOLDS Ralph D. Zweier, Baltimore, Md., assignor to Bethlehem Steel Company, a corporation of Pennsylvania Application June 14, 1939, Serial No. 278,990 1 4 Claims.

This invention relates to improvements in steel ingot-casting apparatus, and in particular to ingot mold caps. I

The purpose of caps on ingot molds is, generally speaking, to prevent piping, retard the formation of blow holes and to reduce segregation or at least confine thesegregation to a shallow zone adjacent the top of the ingot. The cap, usually of considerable weight, is placed at v the top of the mold after the mold has been themetal and, through its chilling effect, pro-- motes and accelerates the formation of a thick skin on the top of the ingot. This tends to exert a high back pressure on the reaction promoting gas evolution in the molten metal and causes a diminution in the amount of gas evolved within the ingot thereafter.

The type of cap heretofore used, however, has been generally convex or flat on the face com ing in contact with the molten metal, and has been found to be unsatisfactory in that, after removal of the cap and consequent removal of pressure from the ingot and heating up of the frozen top skin of the ingot, there tended to take place an eruption of molten metal from the top of the ingot, due to structural weakness of the skin formed thereon.

I have discovered that if, instead of a convex or simple flat face on the cap, a corrugated face he used, the above mentioned difficulty is overcome. I show such a cap in the accompanying drawings, in which Figure l'is a side elevation of my improved Fig. 2 is a section along the line 22 of Fig. 1;

Fig. 3 is a section through a mold in which an ingot has been cast, showing my cap in position thereon, and

Fig. 4 is a perspective view of the top portion of an ingot after removal of my improved cap therefrom.

Referring to the drawings, I show a cap I, having a main body portion 2 and a series of corrugations on the metal-engaging face which alternately extend outwardly from the face and recede into the face. It will be obvious that the iro appearance to the face, or in fact almost any form of projection may be used which will form ribs or indentations in the top-skin of the I ingot, since these ribs or other indentations serve to impart to the top skin of the ingot greatly increased structural strength. In Figure 4, for example, is shown an ingot produced with my improved cap, which illustrates the ribs formed on the top of the ingot by the particular cap hereinafter described. It must of course be borne in mind-that accommodation must be made for the molten metal displaced by the outwardly extending ribs 3 or other projection. I have shown such accommodation in the recessed portions 4 of the cap I. The cap is provided with lifting rings 5 to permit of its/handling by a crane.

Referring to Figure 3, it will be seen that I position my cap at the topof mold 6 with its face in contact with molten metal I. The metal displaced by ribs 3. is accommodated by recesses, 4. In the particular form of cap illustrated, I

have shown it as having longitudinal recesses 8 which may also receive molten metal. These recesses may, however, be omitted.

My improved cap has been successful in overcoming difficulties heretofore encountered for a two reasons: first, the increased area of the surface which is brought in contact with the molten metal gives the cap a greater chilling effect, thus promoting and speeding up the formation of a top-skin on theingot; second, the ribs formed in the top-skin on the ingot naturally result in the skin having a greater structural strength. The result is a top-skin of sufficient thickness and strength to prevent eruption of metal and gases after removal of the cap.

While I have described my invention in one particular phasethereof, I do not wish to be limited to the specific details thereof, as it will be apparent that numerous variations might be constructed without departing from the spirit and scope of my invention.

' Having thus described my invention, what I. v claim asfnew and desire to secure by Letters Patcut is: v

1. A cap for ingot molds comprising a body portion having a face, a plurality of ribsextending outwardly from said face and a pluralityof recesses extending inwardlyfrom said face.

2. A capfor ingot molds comprising a body I portion having a face, a plurality of parallel ribs corrugations may be varied in shape and numher. For example, I may provide the face of my cap with two sets of corrugations, one transverse extending outwardly from said face and a plurality of parallel recesses extending inwardly from said face. I

3. A cap for ingot molds comprising a body portion having a face, a plurality of parallel ribs extending outwardly from said face and a plurality of parallel recesses extending inwardly from said face positioned intermediate said ribs.

4. A cap for ingot molds having a bottom face, 5 a rib extending outwardly of the face and extendribs extending outwardly from said face within the boundary of the first mentioned rib and recesses extending inwardly from said face disposed intermediate said parallel ribs, the ends of said latter ribs and said recesses terminating short of said first mentioned rib.

RALPH D. ZWEIER. 

